Just last month, the social networking giant spent $19 billion on mobile messaging service WhatsApp.

"These are both incredibly rare companies, you shouldn't expect us to do this frequently," said Zuckerberg. "But WhatsApp has the potential to reach a billion users, and any company that can do that will be incredibly valuable. And not many companies are working on what could be the next computing platform (like Oculus VR). The rate (of these acquisitions) won't continue."

Zuckerberg added that in purchasing the Irvine, Calif., company, which has yet to release a product to consumers, Facebook isn't getting in the hardware game. Rather, "we view this as a software and services thing, a network (accessed through Oculus goggles) where people can communicate and buy things, that'll be where the business will come from."

What Zuckerberg made abundantly clear on the 30-minute call was that Facebook's interest in Oculus goes well beyond the virtual-reality gaming world that inspires the company's leader, 21-year-old wunderkind Palmer Luckey. Similarly, Oculus CEO Brandon Iribe noted that his company's interest in joining forces with Facebook stemmed from that same realization about a socially networked world that isn't tied to phones.

"We saw that (Oculus Rift goggles) would be a lot about gaming and entertainment, but we didn't see how big the social experience was," said Iribe. "When you feel you're present in another space, something changes and you start to realize how big this can be. If you can look at (another person) and your brain believes they're in front of you, you get the goose bumps. You see how big an impact it'll be on social."

Zuckerberg said Oculus appealed to him because the company was "so far out front" on the technological VR curve, thanks in part to its ability to use sophisticated (smartphone-derived) technology whose costs are dropping "for the purpose of intense graphics work that won't make you motion sick."

"As soon as you move your head, you have to generate an updated world in 15 to 20 milliseconds. This (Oculus) team now can do that at cost effective price."

The Facebook CEO hinted that his company had briefly considered what it would take to go it alone in the VR space, but quickly determined that "in addition to us being behind, they already had best people in the industry.

"But we were thinking about what the next platforms (for social communication) might be, and though it might take five to 10 years, like smartphones, which popped up in 2003 but got big 10 years later, we thought this is the team we want to work with," he said. "The bigger question on their side was they had so many options. But we got excited about what we could add to each others efforts.

Zuckerberg deflected questions about when a Rift goggle might come to market or whether Oculus executives would take a seat on Facebook's board.